Hey guys . This will be my first post aside from the one in the new members section. I need to first say that I know a good deal about gasoline engines but diesels are new to me and the 1984 Volvo 240 Diesel is my first . I have the Bosch book on the injector pump and the service manual for the D24 . I'm learning as much as I can pretty quickly on the engine .

My first adjustment to the engine was on the enrichment screw . I leaned it back every so slightly and cut down on a decent amount of unspent fuel out the exhaust . The first tank of fuel I put through it I worked out 18mpg and now I am on the second and I am estimating that I will come out with 21mpg .

This diesel has the BW55 so I know I won't get as much as I would with the M46 but I still think I could get 25 mpg. And I still think I have some room to lean the fuel a little more .

I would like to know some thoughts and ideas within reason. I don't want to deviate too much from stock and I want to keep this diesel as classic as possible . I would also like to get the maximum MPG out of this engine while not compromising the engine or any components . The car has 90,000 original miles on it . A lot of stuff has been rebuilt , fixed and upgraded as well . If needed I can list it out .

240 with D24 should get high 20's MPG. Check air filter, timing, exhaust obstruction, tire pressure, etc. Do you see a lot of smoke out the exhaust?

I'm going to list off what it has recently had done just this year .

-New timing belts were put on and the engine was timed
-new water separator
-new glow plugs and buss bars cleaned
-1 fuel injector is new and all of the injector heat shields are new
-all injector bores were cleaned out
-new V belts
-the injection pump was dismantled, cleaned, and resealed with Bosch viton seals including the rear main pump seal.
-the fuel delivery pipes were replaced with a good used set .

All of this work was done by the PO which I would trust with any of my cars especially this diesel ! He is the one who brought this beast back to life and saved it in the first place .

I will be pulling and changing the air filter today . In the first tank I used a fairly good lubricity additive and the second as well . To be honest I want to run Agri diesel but I need to set up a tank for that at some point in time .

The car runs great and performance is better than I expected vs the reviews on a Volvo diesel . There is still black smoke (unspent fuel) coming out at times . I usually let the engine warm up before driving it . It seems hard to tune the enrichment because I think I don't see smoke but then sometimes I do so I may try to set up a white sheet or towel behind the tail pipe next time . I think she can fair to be leaned out a little more . Obviously I understand I will get some loss do to the fact it's a NA engine and not as efficient as the turbo model . It's a slow and steady car . I happen to love it to be honest . It's the most comfortable smooth driving 240 I've ever owned .

I never had an NA D24, but I'd think you should be doing significantly better than my Cummins 4x4....

How is the performance?
timing and advance function are key to good MPG. I'd verify initial timing, and that internal pressure rises with RPM, especially if it's incredibly doggy over 3000 RPM.

Performance is fairly good for what it is . The one thing about it is when it gets up into the RPMs it really starts to dump the fuel out . Because it's an auto it only has the 3 gears and if I floor the pedal and it gets up to around 4k (I'm guessing here) it will start a smoke screen but performance is not hindered .
It's not as bad as it sounds really but maybe I can take a video soon. I don't drive the car hard at all though. I try to dive it rather conservatively .

I do not have a tach in the car . I take it you have a 740 D24T ? Did that model come with a tach? I read up on how to add a diesel tach by wiring it inside the alternator and yes I know they have inductive racha but it seems way to cheesy and fiddle faddle for me to hose clamp a sensor on the outside of the alternator .

I know that yours is an automatic and ive got a manual m47 on my 245. But im doing 17km/l aka 39mpg. Im running 225/55r16 tires, higher gear i the finaldrive plus and ekstra overdrive from a m46 and still it can make som smoke. When im driving the mainroads with 80km/t aka 50mph the engine goes with about 1550rpm. And i still have to get a turbo and try to increase the distance.

I used to have a 245 D24 with M47 with overdrive, i used to get about 29/30 mpg city driving, but the mpg stayed about the same country driving aswell. The gearbox was very reliable. As far as i can remember the m45 is the 4 speed, the m46 is the 5 speed and the m47 is 4 speed with overdrive. I was told the m45, and m47 were much stronger boxes than the m46. (don't know if it's true or not)

I used to have a 245 D24 with M47 with overdrive, i used to get about 29/30 mpg city driving, but the mpg stayed about the same country driving aswell. The gearbox was very reliable. As far as i can remember the m45 is the 4 speed, the m46 is the 5 speed and the m47 is 4 speed with overdrive. I was told the m45, and m47 were much stronger boxes than the m46. (don't know if it's true or not)

Its not true. The m45 is a 4speed, the m46 i a 4speed with overdrive and the m47 is a 5speed